1. Field of the Invention
The present invention generally relates to power converters and, more particularly, to traveling wave tube amplifier electronic power conditioners.
2. Description of the Related Art
In satellite communications, multiple carrier frequencies are separately amplified by individual high power amplifiers such as traveling wave tube (TWT) radio frequency (RF) amplifiers. A traveling wave tube amplifier is a microwave device that contains a vacuum tube known as a traveling wave tube. In general, a TWT amplifies an RF signal inputted to the device after the signal is received by a receiver of the satellite and demultiplexed through a demultiplexer. The amplified RF signal may then be multiplexed and transmitted through a transmitter. Several voltages must be supplied to the TWT to make it perform its amplification function. TWTs on a satellite are usually integrated with a number of power converters or power conditioners that accept a single voltage from a power bus or a power source and generate the various voltages required for the TWT.
The assembly consisting of the various power supplies and their control circuitry is sometimes called an Electronic Power Conditioner (EPC). An EPC usually contains equal number of high voltage and low voltage converters and their related circuitry. Further, an assembly consisting of a TWT and its EPC is called a Traveling Wave Tube Amplifier (TWTA). Historically, EPCs have been designed as singles to provide power to one TWT, or as duals to provide power to two TWTs. With the increasing power capability of spacecraft, over a hundred TWTAs can advantageously be put on a commercial communication satellite. However, one problem with this approach is the amount of EPC circuitry that every single TWT requires and the high cost of deploying such weight into outer space.
In general, the deployment cost of a spacecraft depends significantly on the spacecraft weight and volume. Weight of a spacecraft, in turn, depends partially on the amount of the power conditioning circuitry in the EPCs that needs to be distributed over the available surface area of the spacecraft. Increasing the number of TWTAs increases the spacecraft weight and the volume needed for containing the EPC circuitry. An increase in spacecraft weight and volume leads to increased spacecraft costs. Thus, there are drawbacks in the conventional systems using multiple TWTAs in a spacecraft. Conventional, multiple TWTA systems increase spacecraft weight and require an undesirably large amount of prime surface area especially for EPC circuitry.
In light of the foregoing, a need therefore exists in the current spacecraft technology for a method that reduces the amount of power conditioning circuitry while maintaining the ability to meet multiple TWT specific requirements.
In one aspect of the present invention, a microwave tube system for use with a spacecraft telecommunication system comprises a microwave tube subsystem, a first voltage converter subsystem electrically connected to and powers the microwave tube system, and a second voltage converter subsystem electrically connected to the first voltage converter subsystem. The microwave tube subsystem includes a plurality of microwave tubes. The first voltage converter subsystem includes a plurality of first voltage converter members. The plurality of the microwave tube members are paired with the plurality of the first voltage converter members on a one-to-one basis through an output connector of the first voltage converter members. The second voltage converter subsystem includes a plurality of second converter members connected in parallel to one another and a first predetermined power output of the second converter subsystem powers the first voltage converter subsystem.
In another aspect of the present invention, a power system for use with a traveling wave tube amplifier system on a spacecraft comprises a power controller, a low voltage converter unit, a high voltage converter unit, and a traveling wave tube unit. The power controller regulates a first power output from a first power supply, such as a solar array, and transforms the first power output into a regulated power output. The low voltage converter unit receives the regulated power output and converts the regulated power output into a first predetermined power output. The low voltage converter unit comprises a first number of low voltage converter members connected in parallel to one another. The high voltage converter unit comprises a second predetermined number of high voltage converter members electrically connected to the low voltage converter unit. The second predetermined number is higher than the first predetermined number. Each of the high voltage converter members receives the first predetermined power output of the low voltage converter unit and generates a high voltage power output for one TWT. There are a plurality of traveling wave tube members. The tube members are paired with the high voltage converter members on a one-to-one basis such that the high voltage output of one of the high voltage members is received by one of the traveling wave tube members. The number of pairs equals the second predetermined number.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims.